The existing frictional electricity-generating devices usually generate electricity by rubbing two friction layers of different materials. When the materials of the two friction layers are different, the electron restriction abilities will be different, thus electron transfer will occur during mutual friction, and opposite charges with the same amount will be generated on the two friction layers, thereby a voltage will be generated. In the prior art, in order to improve friction efficiency, the friction surfaces of the friction layers will usually be treated to increase the surface roughness. However, the process of treating the friction surface is so long, and the techniques for treating the friction surface are relatively complex.